JP3166436B2 - Electronic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device, for example, a photoelectric switch, in which an electronic circuit is housed in a shield case, and an adjusting section of the electronic circuit is operated from the outside.

[0002]

2. Description of the Related Art In a photoelectric switch, an input signal needs to be amplified at a low S / N ratio with a weak input signal. In general, in order to prevent external noise, an electronic circuit is provided in a shield case made of a conductor such as a metal. The shield case is electrically connected to the ground potential of the electronic circuit. The detection sensitivity can be adjusted from outside.

FIGS. 2A and 2B show a photoelectric switch as an example of a conventional electronic device, wherein FIG. 2A is a cross-sectional view, and FIG.
It is a detailed view of a part. In FIG. 2, the photoelectric switch includes an outer case 1, a shield case 5 provided in the outer case, and housed in the shield case 5, for example, a printed circuit board, and the ground potential is connected to the shield case 5. In FIG. 2, an opening 11 provided on the upper surface, an opening 51 provided in the shield case 5 and facing the opening 11 of the outer housing 1, and a convex shape are formed in a part of the outer housing 1. The adjustment frame 31 at the center is inserted from the back side of the opening 11 of the outer case 1 so as to be exposed on the surface of the outer case 1, and the lower surface of the flange 32 on the side is located on the upper surface around the opening of the shield case 5. And an electronic circuit 2 provided below the central portion of the lower surface of the operating portion 3 and rotated by a connecting rod 33 penetrating an opening of the shield case 5.
Adjustment unit 4 comprising a variable resistor for adjusting the detection sensitivity of
, And on the upper surface of the flange 32 of the operation unit 3,
For example, it is composed of an elastic packing 6 made of rubber. And a metal housing case 41 of the adjusting unit 4;
The shield is formed by connecting the lead wire 7 to the ground potential point 21 of the electronic circuit 2 by soldering.

[0004] External noise is shielded by the shield case 5 and the housing case 41 of the adjustment unit 4, and the electronic circuit 2 can be amplified with a high S / N ratio. In addition, 12 and 13 are a light emitting part and a light receiving part, and 14 is an operation display part.

[0005]

In the above-described photoelectric switch, the shield of the detection sensitivity adjusting unit which is operated from the outside is provided between the metal housing case of the adjusting unit and the ground potential point of the electronic circuit. This is done by soldering the lead wires, but this location is very narrow, making the soldering work difficult and time consuming. In addition, soldering has a problem in that the reliability of connection is low and a contact failure is likely to occur.

An object of the present invention is to configure a shield with low man-hours and high reliability in an electronic device in which an electronic circuit is housed in a shield case and an adjusting section of the electronic circuit is operated from the outside. .

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an outer casing, a shield case provided in the outer casing, an electronic circuit housed in the shield case, An opening provided in the outer case, an opening provided in the shield case and facing the opening of the outer case, a convex shape, and an adjustment top at the center of the outer case is exposed on the surface of the outer case. An operation unit which is inserted from the back side and is provided such that the lower surface of the flange on the side thereof is located on the upper surface around the opening of the shield case, and the opening of the shield case provided below the lower surface center of the operation unit. An adjusting portion of the electronic circuit rotated by a penetrating connecting rod;
In an electronic device constituted by an elastic packing provided between a back surface of the outer casing and an upper surface of a flange of the operation unit, a connecting rod of the operation unit penetrates a lower surface of the operation unit. A shield plate is provided which is pressed against the upper surface around the opening of the shield case by packing. The shield plate is pressed into, for example, a connecting rod and fixed to the lower surface of the operation unit.
Further, these electronic devices are configured as photoelectric switches.

[0008]

In the electronic device of the present invention, a connecting rod provided below the central portion of the lower surface of the operating portion and rotating the adjusting portion penetrates through the lower surface of the operating portion, and the back surface of the outer casing and the upper surface of the flange of the operating portion are formed. The shield is pressed by the elastic packing between the shield case and the upper surface around the opening of the shield case, so that this shield plate conducts to the shield case and almost completely covers the shield case opening. Cover. Accordingly, noise from the outside is shielded by the shield case and the shield plate, and the shield plate and the shield case are electrically connected by pressing, so that there is no connection work by soldering, the number of steps is reduced, and the reliability is improved. Further, since the shield plate is press-fitted into the connecting rod and fixed to the lower surface of the operation unit, the number of steps is further reduced. Also,
Since the photoelectric switch has a weak input signal and needs to be amplified at a high S / N ratio, and since the detection sensitivity is adjusted from the outside, this electronic device having a shield configuration with low man-hours and high reliability is configured as a photoelectric switch. To do is purposeful.

[0009]

1 shows a photoelectric switch as one embodiment of an electronic device according to the present invention, in which (a) is a sectional view and (b) is (a).
FIG. The difference between the photoelectric switch of the present invention shown in FIG. 1 and the conventional photoelectric switch shown in FIG. 2 is that a connecting rod 33 provided on the lower surface of the flange 32 of the operation unit 3 and below the center of the lower surface of the operation unit 3. The shield plate 8 made of a conductor such as a metal through which
The shield is configured such that the lower surface of the shield plate 8 and the upper surface around the opening of the shield case 5 are pressed by the elasticity of the packing 6. In this case, since the housing case 41 of the adjustment unit 4 is covered with the shield plate 8, the lead wire 7 between the ground potential point 21 of the electronic circuit 2 and the conventionally required lead wire becomes unnecessary.

The shield plate 8 is pressed by the elasticity of the packing 6 to conduct to the shield case 5 and almost completely covers the opening 51 of the shield case 5, so that external noise is prevented by the shield case 5 and the shield plate 8. Shielded, the electronic circuit 2 can be amplified with high S / N. Further, since the shield plate 8 and the shield case 5 are electrically connected by pressing, there is no connection work by soldering, the number of steps is reduced, and the reliability is improved.

When the adjusting top 31 of the operation unit 3 is operated from the outside, the shield plate 8 rotates about the connecting rod 33, and the gap between the shield plate 8 and the shield case 5 is slid while being pressed. It does not adversely affect the shielding action.

[0012]

According to the electronic device of the present invention, since the shield structure is low in man-hour and high in reliability, for example, the input signal needs to be amplified with a small S / N ratio and the detection sensitivity needs to be adjusted externally. The effect is large when applied to a photoelectric switch to be performed.

[Brief description of the drawings]

FIGS. 1A and 1B show a photoelectric switch as one embodiment of an electronic device of the present invention, in which FIG. 1A is a cross-sectional view and FIG. 1B is a detailed view of a portion P in FIG.

FIGS. 2A and 2B show a photoelectric switch as an example of a conventional electronic device, in which FIG. 2A is a cross-sectional view and FIG. 2B is a detailed view of a portion P in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer case 11 Opening 2 Electronic circuit 3 Operation part 31 Adjustment top 32 Flange 33 Connecting rod 4 Adjusting part 5 Shield case 51 Opening 6 Packing 8 Shield plate

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01H 35/00 H01H 19/00-19/64 H01H 5/00-5/06 H05K 9/00 H01C 1/00-1 / 16 H01C 8/00-10/50

Claims (3)

(57) [Claims] An outer case, a shield case provided in the outer case, an electronic circuit housed in the shield case, an opening provided in the outer case, and an electronic circuit provided in the shield case. An opening facing the opening of the outer case, a convex shape is inserted from the back side of the outer case so that an adjustment top at the center thereof is exposed on the surface of the outer case, and the lower surface of the flange at the side is the shield case. An operating unit provided on the upper surface around the opening of the electronic circuit; and an adjusting unit for the electronic circuit, which is provided below the center of the lower surface of the operating unit and is turned by a connecting rod passing through the opening of the shield case. In an electronic device configured by an elastic packing provided between a back surface of the outer casing and an upper surface of a flange of the operation unit, a connecting rod of the operation unit penetrates a lower surface of the operation unit. To the packing Electronic device characterized in that a shield plate is pressed against the upper surface of the peripheral opening of the shield case I. 2. The electronic device according to claim 1, wherein the shield plate is press-fitted into the connecting rod and fixed to the lower surface of the operation unit. 3. The method according to claim 1, wherein
An electronic device comprising a photoelectric switch.